Field of the Invention
The present invention relates to an actuator provided with a device for locking a movable element. The invention can be used for example in the field of aeronautics for locking an aileron or a flap on an aircraft. The actuator may be linear or rotary.
Brief Discussion of the Related Art
An actuator comprises a stationary structure and an actuating element which is movable relative to the stationary structure. In the aeronautics industry, the general trend favors actuators comprising a rotary electric motor driving a motion transmission system making it possible to push or pull a lever integral with the element to be moved.
The actuator generally comprises a device for locking the actuating element in position so as to prevent any accidental motion of the movable element when the electric motor is no longer powered, for example after a failure.
The locking device has a state for releasing the actuating element dedicated to a normal mode of operation of the engine and a locking state dedicated to an engine failure mode. The rotationally locking device generally comprises a stator, a rotor so mounted as to pivot about a pivot axis, at least one locking element mounted between the stator and the rotor so as to be movable between a position of interaction with the rotor and the stator and a position retracted relative to the rotor, and means for actuating the locking element between such two positions.
The device may be so arranged as to prevent the rotation of the rotor whatever the direction of rotation. Alternately, the device may be so arranged as to prevent the rotation of the rotor in only one direction of rotation and to enable the free rotation in the opposite direction.
The device of the latter better-known type is a free-wheel unit, the locking member of which is a pawl or a roller which is returned to the interaction position by a resilient return element. The rotor is then free to rotate in one of the directions of rotation, whereas the locking element opposes the rotation of the rotor in the other direction of rotation.